1. Field of the Invention
The present invention relates to a cable modem device which is capable of reducing unnecessary signals inputted into a circuit substrate to process signals and a signal terminal from the outside and unnecessary radiation caused by the circuit substrate.
2. Description of the Related Art
Miniaturization or unitization (a cable modem device is incorporated into another device that is simultaneously used without being formed as a single device) has been required in a cable modem device which receives signals from the outside via an RF cable (coaxial connector) or which transmits the signals processed in an internal circuit to the outside.
When the unitized cable modem device, that is, a cable modem unit is incorporated into another device, unnecessary signals have to be sufficiently inhibited from being superposed upon received signals processed by the cable modem unit (circuit substrate) or signals generated in the circuit substrate, and unnecessary radiation from the circuit substrate has to be also inhibited from leaking to the outside.
To achieve this, the circuit substrate is housed in a shield case in order to inhibit the unnecessary signals from being superposed upon the received signals or the signals generated in the circuit substrate and to inhibit the unnecessary radiation from the circuit substrate from leaking to the outside, and this has already and broadly been performed.
In Jpn. Pat. Appln. KOKAI Publication No. 3-224295, an assembly structure of a modem housing has been proposed in which the periphery of the substrate is covered with upper/lower covers (including side surfaces), front panel, and rear panel that are molded of a resin material having elasticity.
Moreover, in Jpn. Pat. Appln. KOKAI Publication No. 2002-16524, a transmission/reception integral high-frequency device has been proposed in which a coaxial cable attaching portion is integrally disposed on the substrate and four surfaces of the substrate are covered with shield plates to enhance a communication grade.
In accordance with the examples of the constitutions described in the Jpn. Pat. Appln. KOKAI Publication Nos. 3-224295 and/or 2002-16524, even when the circuit substrate (cable modem unit) is shielded in a shield case, a configuration suitable for incorporation into another device or an arrangement or special structure of a terminal group for use in transmission/reception with respect to the other device has not been considered much.
Moreover, in a case where the circuit substrate housed in the shield case, that is, the cable modem unit is incorporated into the other device, there is a problem that assembly efficiency drops, for example, in a step of attaching an RF connector, because there is little room in space in accordance with a demand for miniaturization.
It is to be noted that, for example, in a case where the terminal group from the circuit substrate extends in a direction different from that of the RF connector, when the RF connector and circuit substrate housed in the shield case are housed into an exterior case having little room (gap), there is a problem that the terminals (in the group) are broken or deformed.